The optimal ratio of diisocyanate to polyol for the synthesis of polyurethane with desirable properties such as tensile strength and elasticity depends on the specific application and desired properties of the final product. However, a general guideline is to maintain a 1:1 molar ratio of isocyanate groups NCO to hydroxyl groups OH in the reaction.This stoichiometric ratio ensures that all the isocyanate and polyol groups react completely, forming a well-defined polyurethane network with balanced mechanical properties. Deviations from this ratio can lead to changes in the final properties of the polyurethane, such as increased brittleness or reduced tensile strength.It is important to note that the optimal ratio may vary depending on the specific diisocyanate and polyol used, as well as the presence of other additives or catalysts in the reaction. Therefore, it is essential to conduct experiments and optimize the formulation for each specific application.